Air-conditioning system



April 14, 1925.

W. B. HODGE AIR CONDITIONING SYSTEM Filed Dec. 18, 1923 2 Sheets-Sheet 1alibo'z 11015 April 14, 1 925.

W. B. HODGE AIR CONDITIONING SYSTEM Filed Dec. 18, 1923 2 Sheets-Sheet 2Patented Apr. 14, 1925.

UNITED STATES 1,533,859 PATENT OFFICE.

WILLIAM B. HO'IDGE, OF CHARLOTTE, NORTH CAROLINA, ASSIGNOR TO PARKS-CRAMER COMPANY, OF FITCHBURG, MASSACHUSETTS, A. CORPORATION 01'MASSACHUSETTS.

AIR-CONDITIONING SYSTEM.

Application filed December 18, 1923. Serial No. 681,439.

To aZZ whom it may concern:

Be it known that I, WILLIAM B. HODGE, a citizen of the United States,residing at Charlotte, in the county of Mecklenburg and State of NorthCarolina, have invented certain new and useful Improvements inAir-Conditioning Systems, of which the following is a specification.

This invention relates to air conditioning apparatus, and particularlyto central station systems for heating and humidifyin% air anddelivering it to buildings.

uch systems customarily draw their supply of air partly from out ofdoors, and partly from a return duct leading from the building, and thespray heads used to hu- Inidify the air wash out of the air considerablequantities of dirt and'lint. A considerable portion of the water-sprayedto humidity the air is precipitated either directly or in the ehminatorscustomarily used, and in order toconserve this water and again feed itto the spray heads, it is necessary to remove from it the dirt and lintwhich it has washed from the air.

This function has heretofore been performed chiefly by screens, whichhave given serious difiiculty, first because they are difficult to cleanwithout shutting down the plant, and second, because they will passslender elongated particles, which cause serious trouble in the sprayheads.

The present invention involves the use of a granular bed filter such,for example, as a sand or gravel bed filter. This arrangement has twooutstanding advantages. First, it is peculiarly effective in removinglint and fine particles from the water, and second, it can readily becleaned by backwashing, while the air conditioning plant continues inoperation.

A preferred embodiment of the invention is illustrated in theaccompanying drawin ,in'which:

Fig. 1 is a vertical axial section through the air conditioning duct ofa central station system;

Fig. 2 is a sectional plan view thereof on the line 22 of Fig. 1.

Fig. 3 is an enlarged section through a lateral showing the branches;

Fig. 1 is a section on line 4-4 of Fi 3. The duct is usually constructedof s eet metal as indicated at 5. Air enters from when it is desired toheat the air.

out of doors, under the control of adjustable louvres 6, and from thereturn duct under the control of adjustable louvres 7. These louvres arecontrolled in any usual manner to regulate the proportions of thereturnair and fresh air.

This air flows to the right, relatively to F ig.-1, and first passesthrough water spray issuing from the spray heads or nozzles 8, mountedon the vertical pipes 9. These pipes 9 are fed from a header 10, whichin turn receives its supply from a centrifugal or other pump 11. Thepump 11 is driven by an electric motor 12 or by any other suitablemeans. After the air has passed through the spray from the nozzles 8, itpasses through eliminators 13 of any suitable construction, which removefrom the air any excess moisture. After passing through theseeliminators, the air flows through heating coils 14, andpasses thence tothe fan 15, which discharges it through the duct 16 to the building. V

The heating coils 14 are operated onllly T esupply steam connection isshown at 17 and the condensate drip connection at 18. The

particular form of the heating coils, the

heating medium used, and the manner of contro ing the coils are allsubject to variation, as will be readily understood by those skilled inthe art.

Any precipitated spray from the nozzles 8, and also the water removedfrom the air by the eliminators '13, flows directly into a granularfilter bed 19, consisting of a bed of gravel, of suitably selected size,contained in a tank 20, mounted in the duct 5 beneath the spray nozzles8 and the eliminators 13. The water flowing down through the gravel bedis carried away through a drain structure mounted near the bottom of thebed 19, and consisting in the examp-1e illustrated, of a main 21, havinga plurality of oppositely extending laterals 22. Each of the laterals 22is provided with a plurality of arms or branches 23, transverselyslotted on their lower sides as clearly indicated at 24. The right-handend of the main 21 is plugged as shown at 25, and similarly the outerends of all the laterals 22, and branches 23, are closed. Consequently,the water drawn from the bottom of the filter bed 19 through the main21,

must enter through the slots 24, and these are so dimensioned as topreclude the entrance of any particles of gravel.

The main 21 opens at 26 into a sump 27, known as the clear-well, and itis controlled by a valve 28, which is operable from a point outside theduct 5, by means of a handwheel 29.

When the valve 28 is open, the water seeping downward through the filterbed 19 flows by way of the main 21 to the clear-well 27 Since a certainamount of sprayed water is taken up by the air-current, it is necessaryto provide make-up water, which is admitted to the clear-well 27, fromany suitable source, through the pipe 30, controlled by the valve 31.

The ump 11 draws its entire supply of water ii'om the clear-well 27through the pipe 32. The intake end of the pipe 32 is provided with afitting 33, into which steam is injected through the pipe 34, thepurpose being to heat the water fiowin to the pump 11. The steam supplythrougi the pipe 34 is controlled by a valve 35, or in any othersuitable manner.

A pipe 36 leads to the main 21, and to it leads a water supplyconnection 37, controlled by a valve 38, and an air supply connection39, controlled by a valve 40. An overflow 41, .whose inlet is slightlyabove the top surface of the filter bed 19, serves as the means forcarrying off the back-wash water and the dirt, and hence leads to anysuitable discharge.

The operation of the louvres 6 and 7, spray nozzles 8, eliminators 13,heating coils 14, and fan 15, are familiar to those skilled in the art.Briefly, they control the admission of the air, its humidification, theremoval of excess moisture, the heating of the air, and its delivery tothe building.

In the operation of the device a certain amount of moisture is preciitated. It flows upon the filter bed 19, w ich operates to remove thedirt and lint, the latter being retained upon or near the top of the bedwhile the water percolates through the bed. Clear water thus entersthrough the slots 24 and flows by way of the laterals 22 and main 21,through valve 28, which is normally open, to clear-well 27. From thewell 27, this water, together with a certain amount of make-up watersupplied through pipe 30, is drawn through heater 33 by pump 11. Thepump 11 discharges it through header 10 to spray nozzles 8.

When it becomes necessary to clean the filter bed 19, the valve 28 isclosed by means of the wheel 29, which, as stated, may be operated froma point outside the duct 5. Pump 11 continues in operation, and theclear-well 27 is then fed with water only by the make-up connection 30.Back-washing is then effected in either of two ways. The

first is to admit air alone, under a. moderate pressure, through thevalve 40, pipe 36, main 21, laterals 22, and branches 23. This airissuing from the slots 24 over substantially the entire area of thefilter bed 19 will produce violent ebullition at the surface of the bed19. Since the valve 28 is closed, water from the spra heads will rapidlyaccumulate in the ta of the overflow 41, will carry away the dirt andlint freed by the ebullition of the bed.

The second, the more rapid way, is simultaneously to admit air, by wayof the valve 40, and water, under a proximately the same pressure, byway 0 valve 38. This increases the rate of outflow of water through theoverflow 41, and produces a definite upward flow of water through thebed 19. Consequently, the cleaning of the filter bed by this method ismore rapid and complete. As soon as the bed has been cleaned, the valves38 and 40 are closed, and the valve 28 is opened.

It will be observed that this apparatus for removing impurities from thewater offers marked practical advantages. It is peculiarly effective asa strainer, and 1t may be cleaned while the air conditioning plantcontinues in operation. Such cleaning is thorough, and is brought aboutwithout the use of complicated apparatus.

Some changes in the specific embodiment of the device are obviouslypossible, and are contemplated. The exact size and nature of the filterbed will vary somewhat with the nature of the plant, and with thecharacter of impurities carried by the air treated. I use the termfilter of the granular bed type as a generic term in this connection.

What is claimed is:

1. In an air conditioning plant, the combination of an air duct; meansfor propelling air therethrough; water Sprayers in said duct; means forcollecting water pre cipitated in said duct; a pump connected to drawwater from said collecting means and feed it tosaid sprayers; a filterof the granular bed type associated with said collecting means andarranged to filter the collected water on its way to the pump; means fordisconnecting saidfilter from said collecting means; auxiliary means forsupplying water to said sprayers; means for producin a reverse flow ofwaterthrough said filter d to back-wash the same; and an over-flowpositioned above the normal water level on said bed and serving to carryofi the back-wash water and water precipitated from said spray headsduring the backwashing operation.

2. In an air conditioning plant, the combination of an air duct; meansfor propelling air therethrough; water sprayers in 88.1

20, and, flowing off by way.

duct; a filter of the granular bed type Ill arranged to receive Waterprecipitated in said duct; a reservoir fed by water passing said filter;an auxiliary Water supply for said reservoir; a pump connected to drawwater from said reservoir and feed it to said sprayers; means forcutting off communication between said filter and reservoir; andconnections'for supplying air under pressure through the discharge ofthe filter to back-wash the latter.

3. In an air conditioning plant, the combination of an air duct; meansfor propelling air therethrough; water sprayers in said duct; a filterof the granular bed type arranged to receive water precipitated in saidduct; a reservoir fed by water passing said filter; an auxiliary watersupply for said reservoir; a pump connected to draw water from saidreservoir and feed it to said sprayers; means for cutting offcommunication between said filter and reservoir; and connections forsupplying water and air under pressure through the discharge of thefilter to back-wash the latter.

4. In an air conditioning plant, the combination of an air duct; meansfor propelling air therethrough; water sprayers and eliminators in saidduct; a granular filter bed beneath said sprayers and eliminators; areservoir; a branched drain leading from closely spaced inlets submergedin said bed, to said reservoir; a valve controlling said drain; meansfor delivering water from said reservoir to said sprayers; auxiliarymeans for supplying water for said sprayers; and connections to saiddrain arranged to supply fiuid under pressure for back-washing saidfilter bed.

5. The combination of a water spraying humidifier of the type in whichexcess Water precipitated from the humidified air is returned to thesprayers and again sprayed; a filter of the granular bedtype interposedin the path of the returning water; connections for back-washing saidfilter including means for cutting off the return flow from the filterto the sprayers; and an auxiliary water supply for said sprayers servingto compensate for the spray evaporation and to keep the sprays in actionduring the back-washing'operation.

6. The combination of a water spraying humidifier of the type in whichexcess water precipitated from the humidified air is returned to thesprayers and again sprayed; a filter of the granular bed type interposedin the path of the returning water; means for cutting 01f the returnflow on the discharge side of the filter; means for backwashing thefilter by fluid under pressure admitted through the filter discharge;and an independent water supply for said heads.

In testimony whereof I have signed my name to this specification.

WILLIAM B. HODGE.

